FEED YOUR LOCAL MONARCHS

Butterflies need nectar sources to fuel their life as winged adults. Among backyard plants that will do the job are asters, black-eyed Susans, butterfly bush, cosmos, goldenrods, joe-pye weed, purple coneflowers, sedums, verbenas and yarrows.

Monarchs uniquely need milkweeds — the only plant on which they will lay eggs and the only plant that caterpillars eat. By consuming the leaves, they ingest the plant’s toxic compounds, making both larvae and adult butterflies unpalatable to predators. Three species native to New Jersey are: Asclepias incarnata, swamp milkweed; Asclepias syriaca, common milkweed; and Asclepias tuberosa, butterfly weed.

• The Monarch Monitoring Project conducts public tagging demonstrations during the fall at Cape May Point State Park, in cooperation with New Jersey Audubon’s Cape May Bird Observatory. Call the observatory at (609) 861-0700 or see the calendar of events at njaudubon.org.

• For $25 (which supports research), you can adopt a tagged monarch and find out where it traveled, if it is recovered. For details, contact the Monarch Monitoring Project at Cape May Bird Observatory at (609) 884-2736.

On any given day in September or October, you may notice some large orange-and-black butterflies doggedly winging their way south. It’s the monarchs and what you are seeing is one leg in the most dramatic long-distance journey by any insect.

“For a long time, their winter destination was a science mystery story,” says Dick Walton, director of New Jersey’s Monarch Monitoring Project. “In 1975, it was finally solved — the butterflies east of the Mississippi are headed to traditional wintering grounds in the mountain forests of central Mexico.”

A key tool in unraveling the secrets of monarch migration is tagging programs such as the one run by the MMP for more than 20 years in Cape May. Small stickers fastened to the butterflies’ wings make it possible to track where those intercepted here eventually wind up.

A monarch is tagged during a program offered by the Monarch Monitoring Project in South Jersey.Patti Sapone/The Star-Ledger

Several generations of butterflies are involved in the annual fall trek from Canada and the United States to their winter retreats up to 3,000 miles away.

Each spring, survivors make their way north again, beginning in late February. The first females to arrive in southeastern states lay eggs that produce young that continue on to northern breeding areas.

Scientists aren’t sure how migratory travel clues are passed from one generation to the next. Monarchs gather in sheltered Mexican forests to spend the winter, often in huge numbers. Early in the year, the simultaneous departure of millions of butterflies for points north is ranked as one of the great biological wonders of the world.

On a spectacular fall day last year, the curious gathered at Cape May Point State Park to see how the butterflies are tagged and sent on their way. Between Sept. 1 and Oct. 31, MMP volunteers, who call themselves the “Monarchists,” also take a daily census of butterflies passing New Jersey’s southern tip. Some are captured for
tagging.

How do you transport a bundle of butterflies? Well, you carefully tuck them into small envelopes and pop them into a picnic cooler — the low temperatures ease the monarchs into a sleepy dormancy, warmth and solar power being the catalyst for butterfly flight.

After details of size and condition are recorded, a volunteer carefully scrapes off a patch of scales from the butterfly’s wing. (All butterfly wings are transparent, with tiny scales giving them their brilliant colors.) Once a small sticker is affixed, observers are invited to offer the monarchs a hand — literally — while they warm up and prepare for take-off.

A butterfly that has been tagged in Cape May is released by monitoring project volunteer Carla Johnson, of Lima, Ohio.Patti Sapone/The Star-Ledger

“We’ve recovered some of our butterflies from their Mexican wintering spots, found one that traveled 140 miles in a straight line in a single day and retrieved one tagged here that three days later made it to central Georgia, 600 miles away,” Walton says. “Their migratory path goes down the coastal plain, along the gulf coast of Texas and then into the mountains of Mexico.”

Monarch populations fluctuate, but scientists are concerned about recent declines. Likely culprits are drought, high summer temperatures and the destruction of habitat, some of it turned over to vast fields of genetically altered crops. Last year’s census in Cape May was the third lowest recorded since the program began in 1990, with only 12.74 butterflies seen per hour on average. It was a sharp drop from the previous year’s count of 183 per hour and a small fraction of the peak year’s count (in 1999) of 359.8.

This makes monarch “way stations” — pockets of nectar sources for food and milkweeds for egg laying — important help for a threatened species. It’s one small way the average person can help keep these beautiful butterflies on the wing and in our skies.